Modeling guided wave excitation in plates with surface mounted piezoelectric elements: coupled physics and normal mode expansion

Abstract

Guided waves have been extensively studied and widely used for structural health monitoring because of their large volumetric coverage and good sensitivity to defects. Effectively and preferentially exciting a desired wave mode having good sensitivity to a certain defect is of great practical importance. Piezoelectric discs and plates are the most common types of surface-mounted transducers for guided wave excitation and reception. Their geometry strongly influences the proportioning between excited modes as well as the total power of the excited modes. It is highly desirable to predominantly excite the selected mode while the total transduction power is maximized. In this work, a fully coupled multi-physics finite element analysis, which incorporates the driving circuit, the piezoelectric element and the wave guide, is combined with the normal mode expansion method to study both the mode tuning and total wave power. The excitation of circular crested waves in an aluminum plate with circular piezoelectric discs is numerically studied for different disc and adhesive thicknesses. Additionally, the excitation of plane waves in an aluminum plate, using a stripe piezoelectric element is studied both numerically and experimentally. It is difficult to achieve predominant single mode excitation as well as maximum power transmission simultaneously, especially for higher order modes. However, guidelines for designing the geometry of piezoelectric elements for optimal mode excitation are recommended.

A Review of Electric Impedance Matching Techniques for Piezoelectric Sensors, Actuators and Transducers

“…Rekhi et al [143] also used a single stage L matched topology to realize the network-on-chip or mm-scale off-chip. Ren and Lissenden [144] considered three frequencies to design L-matching networks using Smith chart and ensured the transducer impedance is complex conjugate of the source impedance. Figure 11 shows the predicted amplitude of Lamb wave mode A0 and S0 modes [21] without matching and with matching at 0.35 MHz.…”

“…The predicted Lamb wave mode A0 and S0 amplitudes with (a) no matching network (b) matching at 0.35 MHz. Reproduced with permission from Reference[144], Copyright IOP, 2018.…”

Axisymmetric and non-axisymmetric Lamb wave excitation using rectangular actuators

“…Excitation of Lamb wave in plates has been explored for a decades with a lot of document results [16][17][18][19]. Giurgiutiu proposed a simple and effective method to excite pure mode Lamb wave using piezoelectric actuator through selecting the size and corresponding frequency [20].…”